Middle Rio Grande Regional Water Plan

estrictions (i.e., the water is physically available for withdrawal, and its use is in compliance
with water rights policies) and thus reflects the amount of water available for use by a region.
The assumptions and methods used statewide to develop the demand projections for each water
use category follow. Not all of these categories are applicable to every planning region. The
specific methods applied in the Middle Rio Grande region are discussed in Section 6.5.2.
Public water supply includes community water systems that rely on surface water and
groundwater diversions other than from domestic wells permitted under 72-12-1.1 NMSA 1978
and that consist of common collection, treatment, storage, and distribution facilities operated for
the delivery of water to multiple service connections. This definition includes municipalities
(which may serve residential, commercial, and industrial water users), mutual domestic water
user associations, prisons, residential and mixed-use subdivisions, and mobile home parks.
For regions with anticipated population increases, the increase in projected population (high and
low) was multiplied by the per capita use from the New Mexico Water Use by Categories 2010
report (Longworth et al., 2013) (reduced for conservation as specified above), times the portion
of the population that was publicly supplied in 2010 (calculated from Longworth et al., 2013);
the resulting value was then added to the 2010 public water supply withdrawal amount. Current
surface water withdrawals were not allowed to increase above the 2010 withdrawal amount
unless there is a new source of available supply (i.e., water project or settlement). Both the high
and low projections incorporated conservation for counties with per capita use above 130 gpcd,
as discussed in Section 6.4, on the assumption that some of the new demand would be met
through reduction of per capita use.
For planning purposes, in counties where a decline in population is anticipated (in either the high
or low scenario or both), as a conservative approach it was assumed that public water supply
would remain constant at 2010 withdrawal levels based on the 2010 administrative water supply
(the water is physically available for withdrawal, and its use is in compliance with water rights
policies). Likewise, in regions where the population growth is initially positive but later shows a
decline, the water demand projection was kept at the higher rate for the remainder of the
planning period.
The domestic (self-supplied) category includes self-supplied residences with well permits issued
by the NMOSE under 72-12-1.1 NMSA 1978 (Longworth et al., 2013). Such residences may be
single-family or multi-family dwellings. High and low projections were calculated as the 2010
domestic withdrawal amount plus a value determined by multiplying the projected change in
population (high and low) times the domestic self-supplied per capita use from the New Mexico
Water Use by Categories 2010 report (Longworth et al., 2013) times the calculated proportion of
the population that was self-supplied in 2010 (calculated from Longworth et al., 2013). In
counties where the high and/or low projected growth rate is negative, the projection was set
equal to the 2010 domestic withdrawal amount. This allows for continuing use of existing
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